Stent introducer system

ABSTRACT

A stent delivery system for positioning a first and second stent the first and second branch lumens of a bifurcation. The stent delivery system includes stent introducers and a sheath or catheter having a frangible wall. A method of delivering stents to anatomies such as bifurcated ducts or vessels.

RELATED APPLICATIONS

This claims the benefit of U.S. Provisional Application Ser. No.60/558,721, filed Mar. 31, 2004, entitled “Stent Introducer System,”which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

This invention generally relates to medical devices, and moreparticularly to devices for delivering stents to a target anatomy.

BACKGROUND

Stents are elongate tubes that are used to prop open occluded ornarrowed vessels or body lumens. Among other things, stents are oftenused to maintain the patency of the biliary tree, or common bile duct.FIG. 1 is a partial, cross-sectional view of a biliary system 2 showingthe common bile duct 2 a, the left hepatic duct 2 b, the right hepaticduct 2 c, the gall bladder 2 d, the pancreas 2 e and the duodenum 2 f.

Strictures or occlusions that develop in the upper common bile ductand/or the left and right hepatic ducts can interfere with the properdrainage of those ducts. FIG. 2 illustrates a partial cross-sectionalview of the biliary system 2 having strictures 3 within the common bileduct 2 a, the left hepatic duct 2 b and the right hepatic duct 2 c. Onemethod of establishing proper drainage through the diseased ducts is toprop open the ducts by placing stents, such as self-expanding biliarystents, within the diseased ducts. Because of the branched configurationof the duct anatomy it is often necessary to place two or more stents inan overlying or side-by-side configuration.

However, currently available stent and introducer geometries are suchthat placement of a first stent often impedes placement of a secondstent. FIG. 3 illustrates the problems associated with the prior artmethod of placing stents in the common bile duct 2 a and the left andright hepatic ducts 2 b, 2 c. That is, placing stent 16 within thecommon bile duct 2 a and the left hepatic duct 2 b impedes subsequentaccess to the stricture in the right hepatic duct 2 c. This preventsplacement of a stent in the right hepatic duct 2 c.

FIG. 3A illustrates one problem encountered in the prior art by placingtwo stents sequentially. That is, once the first stent is deployed, itimpedes insertion of the second introducer 20 used to deploy the secondstent. An alternative to sequential deployment of the stents issimultaneous deployment. Simultaneous deployment, however, requires theside-by-side arrangement of two stent introducers within the workingchannel of an endoscope. Depending on the size of the stents to beplaced and the limited size of the working channel of the endoscope,this option may be unworkable.

Consequently, there is a need for a self-expanding stent delivery systemwhich overcomes the problems associated with prior art delivery systems.Specifically, there is a need for a self-expanding stent delivery systemwhich allows the physician to sequentially place a first and secondstent in the side branches and main lumen of a bifurcation.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide amedical device, method, and kit having features that resolve or improvoeon one or more of the above-described drawbacks.

The foregoing object is obtained by providing a stent delivery systemhaving a first introducer used to deploy a first stent, and a sheath orcatheter used to receive a second introducer, which in turn is used todeploy a second stent. The first introducer and the catheter can besimultaneously deployed, for example, in a staggered configuration,through the working channel of an endoscope. Once the first stent isdeployed, the catheter facilitates delivery of the second introducer tothe target anatomy. The catheter or sheath can be splittable.

In another aspect, wire guides are used to guide the placement of thefirst introducer, the catheter, and the second introducer.

In yet another aspect, the foregoing object is obtained by providing amethod of placing at stents in the branches of a bifurcated targetanatomy. The method includes placing a first and a second wire guide ina working channel of an endoscope. The first wire guide is inserted intothe first branch lumen of the bifurcation. The second wire guide isinserted into the second branch lumen of the bifurcation. A firstintroducer and splittable catheter can then be advanced over therespective wire guides to the respective target anatomies. Once inplace, the first stent can be deployed. A second introducer can then beintroduced over the second guide wire, through the splittable catheterand to the proper target anatomy. Once the second introducer is inplace, the second stent can be deployed.

The method of the invention may further include any of the followingsteps: disposing the first introducer and the splittable catheter withinthe working channel of the endoscope such that the first introducerproximal portion is disposed adjacent to the splittable catheter and thefirst introducer distal portion is disposed distal to the splittablecatheter while inside the working channel of the endoscope; deployingthe first stent within the first branch lumen and the main lumen of thebifurcation and withdrawing the first introducer from the bifurcation;and/or splitting the splittable catheter and withdrawing the splittablecatheter from the bifurcation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial, cross-sectional view of a biliary system showingthe common bile duct, the left hepatic duct, the right hepatic duct, thegall bladder, the pancreas and the duodenum.

FIG. 2 is a partial, cross-sectional view of the biliary system of FIG.1 showing strictures within the common bile duct, the left hepatic ductand the right hepatic duct.

FIG. 3 is a partial, cross-sectional view of the biliary system of FIG.2 illustrating a stent that has been placed in the common bile duct andthe left hepatic duct.

FIG. 3A is a partial, cross-sectional view of the biliary system of FIG.1 illustrating a first stent previously placed by a first introducer inthe right hepatic duct and the common bile duct that obscures the accessof a second introducer attempting to place a second stent in the lefthepatic duct and common bile duct.

FIG. 4 is a partial, cross-sectional view of the biliary system of FIG.2 illustrating the placement of first and second stents in the left andright hepatic ducts, respectively, and the common bile duct according toa preferred method of the present invention.

FIG. 5 is a partial, cross-sectional view of a preferred embodiment ofthe stent delivery system of the present invention illustrating a firstintroducer placed within the right hepatic duct and the common bile ductand a splittable catheter placed in the right hepatic duct and thecommon bile duct.

FIG. 6 is a partial, cross-sectional view of the preferred embodiment ofthe stent delivery system of FIG. 5 illustrating a first stent deployedin the right hepatic duct and common bile duct after the firstintroducer has been removed and the splittable catheter placed in theright hepatic duct and the common bile duct.

FIG. 7 is a partial, cross-sectional view of the preferred embodiment ofthe stent delivery system of FIG. 6 illustrating a first stent deployedin the right hepatic duct and common bile duct and the splittablecatheter shielding a second introducer as the second introducer isadvanced over a second wire guide into the common bile duct and the lefthepatic duct.

FIG. 8 is a cross-sectional, end view of the stent delivery system ofthe present invention showing the first introducer and the splittablecatheter within the working channel of an endoscope.

FIG. 9 is a partial, cross sectional, side-view of a preferredembodiment of the stent delivery system of the present invention showingthe first introducer and the splittable catheter within the workingchannel of an endoscope.

FIG. 10 is a cross-sectional view of an embodiment of the firstintroducer of the stent delivery system of the present invention.

FIG. 11 is a partial, cross-sectional view of a distal portion of thefirst introducer of FIG. 5.

FIG. 12 is a partial, cross-sectional view of an alternate embodiment ofthe distal portion of the first introducer of FIG. 5.

FIG. 13 is a partial, cross-sectional view of the distal portion of thefirst introducer of FIG. 5 showing the wire guide and wire guide lumen.

FIG. 14 is a partial, cross-sectional view of the distal portion of thefirst introducer of FIG. 5 showing an alternate embodiment of the wireguide and the wire guide lumen.

FIG. 15 is a partial, cross-sectional view of the distal portion of thefirst introducer of FIG. 5 showing an alternate embodiment of the wireguide and the wire guide lumen.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the Figures wherein like numerals indicate the sameelement throughout the views, there is shown in FIGS. 1-2 and 4 abifurcation having a main lumen, a first branch lumen and a secondbranch lumen. In particular, these figures illustrate a bifurcation inthe biliary system, wherein the main lumen comprises the common bileduct 2 a and the first and second branch lumens comprise the left andright hepatic ducts 2 b, 2 c respectively. FIG. 1 shows a normal, orhealthy, biliary system without strictures. FIG. 2 shows the biliarysystem with strictures 3 residing in the main lumen and in both branchlumens of the bifurcation. FIG. 4 shows a pair of stents placed in theleft and right hepatic ducts 2 b, 2 c, respectively, and the common bileduct 2 a according to a method of the present invention.

Referring now to FIGS. 5-9, a stent delivery system made in accordancewith the present disclosure is shown. The stent delivery system includesa first and second introducers configured to deliver two stents to atarget anatomy, as well as a catheter used to facilitate delivery of thesecond introducer to a target anatomy. The first introducer 10 and thesplittable catheter 50 are adapted to be disposed within the workingchannel 8 a of an endoscope 8 as shown in FIGS. 5, 8 and 9. Asillustrated in FIG. 7, the splittable catheter 50 includes an interiorpassageway through which the second introducer can be advanced.

As illustrated in FIG. 7, the splittable catheter 50 is an elongate,flexible tube adapted to allow the second introducer 20 to advanceunobstructed into the target anatomy. The splittable catheter 50 can beformed from a frangible material, for example, a material that readilytears in a longitudinal direction along the length of the sheath. Anon-limiting example of a splittable material is a molecularly oriented(non-isotropic) polytetrafluoroethylene (PTFE) such as that used in thePEEL-AWAY™ Sheath (Cook Incorporated, Bloomington, Ind.). Alternatively,splittable catheter 50 can be formed from any suitable material known inthe art including, but not limited to, PTFE, polyamide, polyurethane,polyethylene and nylon including multi-layer or single layer structures.The splittable catheter 50 can also be provided with a groove,pre-score, a weakened area or a pre-slit end to facilitate splitting.

Splittable catheter 50 can ranges in size from about 5 Fr. to about 9Fr. These sizes are provided for illustrative purposes only and are notintended to be construed as a limitation of the present invention. Asone of ordinary skill in the art would appreciate in view of the presentdisclosure, the size of the splittable catheter 50 is related to thesize of the second introducer 20 that is advanced through it, which inturn is related to the size of the second stent 26 in its compressed orunexpanded configuration. Thus, splittable catheters smaller than about5 Fr. that may become available in the future are contemplated as beingwithin the scope of the claims of the invention.

With respect to the introducers used with the stent delivery system ofthe present disclosure, any introducer capable of introducing anddeploying stents is contemplated. Non-limiting examples include biliarystent deployment delivery systems as well as the introducers describedin co-pending provisional application Ser. No. 10/728,589 (Attorneydocket number 10000/218), which is incorporated by reference in itsentirety. The introducers can be of the same or different type and size.

FIGS. 10-15 illustrate several, non-limiting, exemplary embodiments ofintroducer 10. In one exemplary embodiment, illustrated in FIG. 10,introducer 10 has a proximal end and a distal end having inner and outercoaxial tubes. The outer coaxial tube forms an outer sheath or catheter11. The inner coaxial tube forms a shaft 13. Shaft 13 has a proximal end13 a, a distal end 13 b and a stent retaining area 15. Optionally, shaft13 may include a pusher band 17 attached to the stent retaining area 15,a distal tip 18 attached to the shaft distal end 13 b and a wire guidelumen 19. Shaft 13 can be made from any suitable material known in theart including, but not limited to, polyethylene ether ketone (PEEK),polytetra-fluoroethylene (PTFE), polyamide, polyurethane, polyethyleneand nylon, including multi-layer or single layer structures and may alsoinclude reinforcement wires, braid wires, coils and or filaments.Preferably, shaft 13 comprises a proximal portion made of a relativelyrigid material such as stainless steel or any other suitable materialknown in the art.

Stent retaining area 15 is preferably located on a distal portion of theshaft 13. The stent retaining area 15 retains a stent 16 to be deployedin the bifurcation. Optionally, stent 16 is a self-expanding stent.

Pusher band 17 helps to prevent the stent from proximally migrating asthe outer catheter 11 is withdrawn proximally to deploy the stent. Thepusher band 17 is located proximal to the stent 16 such that theproximal end of the stent 16 abuts the pusher band 17 as shown in FIGS.10-15.

Distal tip 18 helps prevent fluids from entering the outer catheter 11as the introducer 10 is navigated through the body lumens. As shown inFIGS. 10-15, distal tip 18 has a proximal end 18 a and a distal end 18b. The distal tip proximal end 18 a has a diameter that is less than thediameter of the distal outer catheter distal end 14 b and is receivedtherein. Optionally, the distal tip 18 tapers to a smaller diametertowards its distal end 18 b as shown in FIG. 12. Distal tip 18 can bemade from any suitable material known in the art including, but notlimited to, PEEK, PTFE, polyamide, polyurethane, polyethylene and nylon,including multi-layer or single layer structures.

In the embodiment shown in FIGS. 10 and 13, wire guide lumen 19 extendsthrough the shaft 13, from the shaft distal end 13 b to the shaftproximal end 13 a. In this embodiment, the shaft proximal end 13 aoptionally includes a luer-lock fitting 31 for releaseably fixing a wireguide 32 relative to shaft 13 as shown in FIG. 10. In the embodimentsshown in FIGS. 10 and 13, the stent delivery system 1 of the presentinvention includes an over-the-wire type wire guide. Such wire guidesare known in the art.

Alternatively, the wire guide lumen 19 may extend through the shaft 13from the shaft distal end 13 b to the shaft proximal end 13 a but thewire guide 32 exits through an aperture positioned along the length ofthe introducer 10. For example, as shown in FIG. 14, the wire guide 32extends through a portion of the distal tip 18 and exits through anaperture 30 positioned along the length of the distal tip 18. In thisembodiment, the wire guide 32 extends through the distal tip 18 andexits the introducer 10 without passing through stent 16. For example,wire guide 32 may extend proximally through distal tip 18 for a distanceof about 1 cm.

In the alternate embodiment shown in FIG. 15, the wire guide lumen 19extends through the length of the shaft 13 but the wire guide 32 extendsthrough a portion of the shaft 13 and exits through an aperture 30positioned along the length of outer catheter 11. In this embodiment,wire guide 32 extends through the distal tip 18, through a portion ofthe shaft 13 and passes through stent 16 before exiting introducer 10.For example, wire guide 32 may extend through the distal tip 18 andthrough the stent retaining area 15 for a distance of about 20 cm.

In yet other alternative embodiments, the wire guide lumen 19 may extendthrough a portion of shaft 13 and may exit through an aperture 30positioned along the length of the introducer 10. Any number ofapertures 30 positioned at any location along the length of theintroducer 10 is contemplated. In addition, the wire guide lumen 19 mayalso comprise a channel or split.

Aperture 30 provides the stent delivery system of the present inventionwith rapid-exchange capabilities. In particular, by extending the wireguide 32 through only a distal portion of the wire guide lumen 19, thedelivery system can be removed from a wire guide 32 having a lengthsubstantially shorter than the length necessary if the wire guide 32were extended through the entire length of the wire guide lumen 19.

Referring to FIG. 10, the sheath or outer catheter 11 has a proximal end11 a and a distal end 11 b. Preferably, at least the distal portion ofouter catheter 11 is made of any optically clear or imageable material.This allows the stent 16 mounted on the stent retaining area 15 of theshaft 13 to be viewed.

The outer catheter 11 further includes a proximal outer catheter 12having proximal and distal ends, 12 a and 12 b, respectively, and adistal outer catheter 14 having proximal and distal ends, 14 a and 14 b,respectively. The distal end 12 b of the proximal outer catheter 12 isattached to the proximal end 14 a of the distal outer catheter 14 toform outer catheter 11. The distal end 12 b of proximal outer catheter12 can be attached to the proximal end 14 a of distal outer catheter 14by any method known in the art including, but not limited to, heatfusing, adhesive bonding, chemical bonding or mechanical fitting.Alternatively, the proximal outer catheter 12, and the distal outercatheter 14 can be formed from of a single catheter or sheath.

The introducer proximal outer diameter is between about 5 Fr. and about6 Fr. The first introducer distal outer diameter is between about 6 Fr.and about 6.5 Fr. This allows placement of a stent having a compresseddiameter between about 0.077 inches and about 0.78 inches. These sizesare provided for illustrative purposes only and are not intended to beconstrued as a limitation of the present invention. As one of ordinaryskill in the art would appreciate, the size of the introducer requiredto place a stent is related to the size of the stent to be placed, andmore particularly, to the size of the compressed configuration of thestent. Thus, introducers having distal outer diameters less than about 6Fr. used to place stents having compressed configurations less thanabout 0.078 inches that may become available in the future arecontemplated as being within the scope of the present disclosure.

The first introducer 10 and the splittable catheter 50 are sized to bedisposed next to each other in the working channel 8 a of an endoscope8. More particularly, the sum of the first introducer 10 outer diameter,i.e. either the proximal outer diameter or the distal outer diameter,and the splittable catheter outer diameter is less than the innerdiameter of the working channel 8 a of the endoscope 8. For example,referring to the embodiment shown in FIG. 9, the first introducer 10 andthe splittable catheter 50 are disposed next to each other in astaggered configuration within the working channel 8 a of an endoscope8. That is, the introducer has an increased diameter portion (the stentretaining area) and a decreased diameter portion (the proximal outercatheter). When the introducer and catheter are positioned in anendoscope adjacent to one another and staggered the respective increasedand decreased diameter portions are nested together. As can be seen inFIG. 9, the sum of the first introducer proximal outer diameter and thesplittable catheter 50 is less than the inner diameter of the workingchannel 8 a of the endoscope 8.

In yet another alternate embodiment of the stent delivery system 1 ofthe present invention, the first introducer 10 and the splittablecatheter 50 are sized to also accommodate at least one wire guide 32 or42 within the working channel 8 a of the endoscope 8. For thisembodiment, the sum of the first introducer proximal outer diameter, thesplittable catheter outer diameter and at least one of the first andsecond wire guides 32, 42 is less than the inner diameter of the workingchannel 8 a of the endoscope 8.

The stent delivery system 1 of the present invention is used to placefirst and second stents 16, 26 into a bifurcation having strictures 3 inthe main lumen 2 a and the first and second branch lumens 2 b, 2 c asfollows. Using an endoscope, a distal end of a first wire guide isadvanced into the first branch lumen of the bifurcation. A distal end ofa second wire guide is then advanced into the second branch lumen of thebifurcation. The first introducer 10 and the splittable catheter 50 areadvanced over the wire guide into the working channel 8 a of theendoscope 8. Thus, the first introducer 10 is positioned within thefirst branch of the bifurcation and the splittable catheter 50 ispositioned within the second branch lumen of the bifurcation, as shownin FIG. 5. The first introducer 10 and splittable catheter 50 may bepositioned sequentially or simultaneously. The first introducer 10 ispositioned such that the first stent 16 is at least partially alignedwithin any occlusion of narrowing of the first branch of thebifurcation. Once aligned, the first stent is deployed within the firstbranch of the bifurcation and the first introducer is withdrawn as shownin FIG. 6. After the first introducer 10 is removed, a second introducer20 is passed through the working channel 8 a of the endoscope 8 andadvanced over the second wire guide 42 through the splittable catheter50. FIG. 7 shows that the splittable catheter 50 acts as a shield toprotect the second introducer 20 from being snagged, or otherwiseblocked, by the deployed first stent 16. FIG. 7 also shows thesplittable catheter 50 splitting, or peeling away, as the secondintroducer 20 is advanced through it and into the second branch lumen26. Once the second introducer 20 is positioned in the second branchlumen 2 b, the splittable catheter 50 is removed and the second stent 26is deployed within the second branch lumen 2 b and the main lumen 2 a.The resulting connfiguration is shown at FIG. 4.

The above Figures and disclosure are intended to be illustrative and notexhaustive. This description will suggest many variations andalternatives to one of ordinary skill in the art. All such variationsand alternatives are intended to be encompassed within the scope of theattached claims. Those familiar with the art may recognize otherequivalents to the specific embodiments described herein whichequivalents are also intended to be encompassed by the attached claims.For example, the invention has been described in the context of thebiliary system for illustrative purposes only. Application of theprinciples of the invention to any other bifurcated lumens or vesselswithin the body of a patient, including areas within the digestive tractsuch as the pancreatic system, as well as areas outside the digestivetract such as other vascular systems, by way of non-limiting examples,are within the ordinary skill in the art and are intended to beencompassed within the scope of the attached claims.

1. A stent delivery system comprising: a first introducer comprising afirst stent; a second introducer comprising a second stent; and acatheter having a passageway adapted to receive the second introducer.2. The stent delivery system of claim 1 wherein the first introducer andthe catheter are adapted to be disposed in a partly staggeredconfiguration within the working channel of an endoscope.
 3. The stentdelivery system of claim 2, wherein the first introducer and thecatheter have a combined outside diameter between about 3 mm and 4.5 mm.4. The stent delivery system of claim 1, wherein the catheter furthercomprises a side wall having a frangible portion.
 5. The stent deliverysystem of claim 4, wherein the first introducer comprises a distalportion having a stent retaining portion.
 6. The stent delivery systemof claim 4, wherein the second introducer comprises a distal portionhaving a stent retaining portion.
 7. The stent delivery system of claim4, wherein a proximal portion of the first introducer is positionedadjacent to the catheter and a distal portion of the first introducer isdistal to the catheter when the first introducer and catheter are insidethe working channel of the endoscope.
 8. The stent delivery system ofclaim 1 further comprising a first wire guide, wherein the firstintroducer further comprises a wire guide lumen adapted to receive thefirst wire guide.
 9. The stent delivery system of claim 8, wherein thewire guide lumen extends through at least a distal portion of the firstintroducer.
 10. The stent delivery system of claim 8 further comprisinga second wire guide, wherein the second introducer further comprises asecond wire guide lumen adapted to receive the second wire guide. 11.The stent delivery system of claim 10, wherein the wire guide lumen ofthe second introducer extends through at least a distal portion of thesecond introducer introducer.
 12. A kit for delivering first and secondstents to a branched target anatomy, the kit comprising: a firstintroducer comprising: a tubular body having a proximal end, a distalend, and a stent carrying portion therebetween; a second introducercomprising: a tubular body having a proximal end, a distal end, and astent carrying portion therebetween; a catheter adapted to receive thesecond introducer, the catheter having a frangible wall; and a sterilepackage adapted to receive the first introducer, the second introducerand the catheter.
 13. The kit of claim 12, further comprising: a firstself-expanding stent positioned within the stent carrying portion of thefirst introducer; and a second self-expanding stent positioned withinthe stent carrying portion of the second introducer.
 14. The kit ofclaim 13, further comprising: a first wire guide wherein the first wireguide is configured to receive the first introducer; and a second wireguide wherein the second wire guide is configured to receive the secondintroducer; and wherein the sterile package is adapted to receive thefirst and second wire guides.
 15. The kit of claim 12, wherein the firstintroducer further comprises: a passageway extending between the distalend and a port positioned proximal to the stent carrying portion,wherein the port is adapted to receive a wire guide.
 16. The kit ofclaim 12, wherein the second introducer further comprises: a passagewayextending between the distal end and a port positioned proximal to thestent carrying portion, wherein the port is adapted to receive a wireguide.
 17. The kit of claim 12, wherein the first introducer furthercomprises: a passageway extending between the distal end and a portpositioned distal to the stent carrying portion, wherein the port isadapted to receive a wire guide.
 18. The kit of claim 12, wherein thesecond introducer further comprises: a passageway extending between thedistal end and a port positioned distal to the stent carrying portion,wherein the port is adapted to receive a wire guide.
 19. A method forpropping open a narrowed bifurcated anatomy having a main lumen andfirst and second branch lumens, the method comprising the steps of: a)providing the kit of claim 19; b) providing an endoscope having aworking channel; c) positioning the endoscope adjacent the bifurcatedanatomy; d) advancing the first wire guide through the working channelto the first branch lumen; e) advancing the second wire guide throughthe working channel to the second branch lumen; f) advancing the firstintroducer over the first wire guide to the first branch lumen of thebifurcation; g) advancing the catheter over the second wire guide to thesecond branch lumen of the of the bifurcation; and h) deploying thefirst stent within the first branch lumen.
 20. The method of claim 19,wherein steps f) and g) further comprise advancing the first introducerand the catheter through the working channel in a staggeredconfiguration; and further comprising the steps of: i) advancing thesecond introducer over the second wire guide and through the catheter tothe second branch lumen; j) removing the catheter, thereby splitting thefrangible wall; k) deploying the second stent; and l) withdrawing thesecond introducer.